Generally, wireless transceivers may be severely energy constrained as a result of, among other things, running off a small battery and/or energy scavenging techniques. Thus, as wireless-communication technologies have become more and more pervasive over recent years, so too has the demand for ultra-low power (ULP) wireless transceivers. ULP wireless transceivers have many applications including, as a few examples, as wireless-sensor networks (which may monitor, e.g., geographic areas, industrial processes, and/or transportation systems), body area networks (which may monitor, e.g., physiological conditions of a given patient), and remote controls (e.g., for use in multimedia devices and/or automotives). Many other examples of such applications exist as well.
Generally, a wireless transceiver may include a transmitter and a receiver, among other functional components. That is, a wireless transceiver may include a transmitter that is configured to carry out functions that may include data modulation and signal transmission. A wireless transceiver may also include a receiver that is configured to carry out functions that may include wirelessly receiving a signal and demodulating such a received signal.
While a wireless transceiver may be configured to perform a number of additional functions (e.g, sensing, data processing, data storage, and/or various additional communication functions), the power required by wireless transmission and receipt functions is typically a dominant component of the total power consumed by a wireless transceiver. Therefore, attempts to reduce the overall power consumption of wireless transceivers are commonly directed to improving techniques for reducing the amount of power used to carry out wireless transmission and receipt function.
One aspect of wireless transmission that may be particularly power intensive is carrier-signal generation. In an example transceiver, carrier signal-generation may involve frequency synthesis and data modulation at the carrier frequency, which may require high power expenditures. Common approaches to reducing the power consumed in carrier-signal generation (as well as other transmission functions) merely shift the power-consumption burden from the transmitter side of the transceiver to the receiver side of the transceiver. For instance, one approach to reducing the power consumed in carrier-signal generation during transmission on the transmitter side of the transceiver may be to replace a radio frequency (RF) phase-locked loop (PLL) with an open loop oscillator in the transceiver, which may be less power intensive but may also be less stable than the use of the PLL. However, such an approach requires that the transceiver devote extra power to frequency correction/calibration functions on the receiver side of the transceiver, and therefore does little to meaningfully reduce the total power consumed by the wireless transceiver. Thus, particularly in peer-to-peer applications in which it is desirable that network devices are capable of carrying out both transmission and receipt functions, common approaches to reducing the power consumed by wireless transceivers have proven inadequate.
For some wireless transceiver applications, it may also be desirable that the wireless transceiver be small in size and low in weight. One example of such an application is electromyography, which may involve the evaluation of the electrical activity produced by skeletal muscles by detection and recording of the electrical potential generated by muscle cells. Because electromyography requires on-body recording, it may be desirable to use sensors that are, among other things, small in size, low in weight, and robust/reliable.